species appropriate

01 dog’s parallel evolution with humans and genetic split from wolves

The genetic bases of demographic changes and artificial selection underlying domestication are of great interest in evolutionary biology. Here we perform whole-genome sequencing of multiple grey wolves, Chinese indigenous dogs and dogs of diverse breeds. Demographic analysis shows that the split between wolves and Chinese indigenous dogs occurred 32.000 years ago and that the subsequent bottlenecks were mild. Therefore, dogs may have been under human selection over a much longer time than previously concluded, based on molecular data, perhaps by initially scavenging with humans. Population genetic analysis identifies a list of genes under positive selection during domestication, which overlaps extensively with the corresponding list of positively selected genes in humans. Parallel evolution is most apparent in genes for digestion and metabolism, neurological process, and cancer. 

Link to article : Wang, Gd., Zhai, W., Yang, Hc. et al. The genomics of selection in dogs and the parallel evolution between dogs and humans. Nat Commun 4, 1860 (2013). 


02 plant eating common behavior for domestic dogs

Based on the findings in Study 1, that approximately 79% of healthy, well-cared-for dogs eat plants, particularly grass, plant eating appears to be a common behaviour of domestic dogs. The fact that this behaviour is widespread and occurs in all domesticated breed groups indicates that it likely serves some biological function.

Link to article: Sueda, Karen & Hart, Benjamin & Cliff, Kelly. (2008). Characterisation of plant eating in dogs. Applied Animal Behaviour Science - APPL ANIM BEHAV SCI. 111. 120-132.


03 domestic dogs gene mutations

This research conducts whole-genome resequencing of dogs and wolves to identify 3.8 million genetic variants used to identify 36 genomic regions that probably represent targets for selection during dog domestication. Nineteen of these regions contain genes important in brain function, eight of which belong to nervous system development pathways and potentially underlie behavioural changes central to dog domestication. Ten genes with key roles in starch digestion and fat metabolism also show signals of selection. We identify candidate mutations in key genes and provide functional support for an increased starch digestion in dogs relative to wolves. Our results indicate that novel adaptations allowing the early ancestors of modern dogs to thrive on a diet rich in starch (plant-based diets are rich in starch), relative to the carnivorous diet of wolves, constituted a crucial step in the early domestication of dogs.
Link to article:  Axelsson, E., Ratnakumar, A., Arendt, ML. et al. The genomic signature of dog domestication reveals adaptation to a starch-rich diet. Nature 495, 360–364 (2013). 


coevolution of dog genes and human culture

Extant dog and wolf DNA indicates that dog domestication was accompanied by the selection of a series of duplications on the Amy2B gene coding for pancreatic amylase. In this study, we used a palaeogenetic approach to investigate the timing and expansion of the Amy2B gene in the ancient dog populations of Western and Eastern Europe and Southwest Asia. Quantitative polymerase chain reaction was used to estimate the copy numbers of this gene for 13 ancient dog samples, dated to between 15 000 and 4000 years before present (cal. BP). This evidenced an increase of Amy2B copies in ancient dogs from as early as the 7th millennium cal. BP in Southeastern Europe. We found that the gene expansion was not fixed across all dogs within this early farming context, with ancient dogs bearing between 2 and 20 diploid copies of the gene. The results also suggested that selection for the increased Amy2B copy number started 7000 years cal. BP, at the latest. This expansion reflects a local adaptation that allowed dogs to thrive on a starch rich diet, especially within early farming societies, and suggests a biocultural coevolution of dog genes and human culture.
Link to article:  Ollivier Metal.2016Amy2Bcopy number variation reveals starch diet adaptations in ancient European dogs. Royal Society Open Science.3: 160449.